velocityparser.java

Velocity的实例应用

package com.ibm.dvworks.velocity;

import org.apache.velocity.app.Velocity;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.Template;
import java.io.*;



public class VelocityParser  {

      VelocityContext mainContext = null;
      Template mainTemplate = null;

      public VelocityParser(String templateFile)  {
        try {
            Velocity.init("velocity.properties");
            mainTemplate = Velocity.getTemplate(templateFile);
         }
         catch( Exception ex ) {
                System.out.println("Error processing template file: " + templateFile );
          }
      }

      public void addToContext(String key, Object value) {
          if (mainContext == null)
              mainContext = new VelocityContext();
           mainContext.put(key, value);
     }
      public void addToContext(VelocityContext chainCtx) {
          mainContext = new VelocityContext(chainCtx);
      }
      public VelocityContext getCurrentContext() {
         return mainContext;   
      }
      

     public void processTemplate() {
         try {
            BufferedWriter writer = writer = new BufferedWriter(
                new OutputStreamWriter(System.out));

            if ( mainTemplate != null)
                mainTemplate.merge(mainContext, writer);
            writer.flush();
            writer.close();
        }
        catch( Exception ex )    {
           ex.printStackTrace();
        }
    }

    public static void main(String[] args)    {
        VelocityParser velInstance = new VelocityParser(args[0]);
        velInstance.addToContext(  "treeFarm", new String [] { "redwood", "maple", "oak", "pine" });
        velInstance.addToContext( "title", "A Tree Farm");
        velInstance.addToContext( "date", new java.util.Date());
        velInstance.addToContext("fmtr", 
        new org.apache.velocity.app.tools.VelocityFormatter(
                  velInstance.getCurrentContext()));
        velInstance.processTemplate();             
    }
}